This article is about the astronomical phenomenon. The term has traditionally referred to an “extra” moon, where a year which normally has 12 almanac com extra pdf has 13 instead. 24 days divided by 29. Each calendar year contains roughly 11 days more than the number of days in 12 lunar cycles.
The extra moon necessarily falls in one of the four seasons, giving that season four full moons instead of the usual three, and, hence, a blue moon. Lenten moon came at its expected time. The occasional 13th full moon that came too early for its season was called a “blue moon”, so the rest of the moons that year retained their customary seasonal names. The frequency of a blue moon can be calculated as follows. Given that a year is approximately 365.
2425 days and a synodic orbit is 29. 368 synodic months in a year. Thus it would take about 2. 716 years, or 2 years, 8 months and 18 days for another blue moon to occur.
February, with only 28 or 29 days, has no full moon. Under this misinterpretation a blue moon can be more frequent. The intention may simply be that Jeffrey makes an absurd statement, “the moon is blue”, to make the point that priests require laymen to believe in statements even if they are patently false. But in the above interpretation of “betrayer moon”, Jeffrey may also be saying that it is up to the priests to say when Lent will be delayed, by announcing “blue moons” which laymen have no means to verify.